The long-term objective of the project is to understand the molecular and cellular pathology of autosomal dominant polycystic kidney disease (ADPKD), one of the commonest genetic diseases of man. Despite the frequency of ADPKD (1/1000) and the fact that it accounts for 10% of all chronic dialysis and transplantation, limited progress has been made in our understanding of its pathogenesis and no specific therapy is available to retard the development of renal cysts or the progression to end-stage renal failure. Moreover, genetic counseling has been hindered by the lack of a reliable universal method for early carrier detection. The proposed project will exploit the techniques of 'reverse genetics' to isolate and clone the ADPKD gene in order to investigate its molecular pathology. In preliminary studies. the ADPKD locus has been mapped between two flanking genetic markers on the distal third of the short arm of chromosome 16 (16p13). These studies will be extended to construct a restriction map of the region between the flanking markers using pulsed-field electrophoresis (PFE). Large DNA fragments prepared by inverted field electrophoresis will be subcloned and screened for candidate sequences for the ADPKD gene. The genomic and cDNA counterparts of the gene will then be cloned and used to study its organization. The protein sequence will be deduced from the DNA sequence and compared with known sequences. ADPKD probes will also be used to study the relationship between phenotype and genotype in patients with a wide variety of clinical patterns of the disease. This analysis should lead to a reliable means of carrier detection by direct molecular analysis, and may provide useful prognostic indicators. Finally, in vitro expression of the cDNA will be used to raise polyclonal antibodies to the ADPKD polypeptide. These antibodies will be used to study the temporal pattern of expression and tissue distribution of the ADPKD protein.